They could hurt local fish population, but probably can’t endure the winter

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JANESVILLE, Wis., Sept. 24 — A carnivorous alien fish known for its voracious appetite and ability to wriggle short distances on land has been found in southern Wisconsin’s Rock River. The discovery of the 2-foot-long giant snakehead by the state Department of Natural Resources marks the first time the species, a native of Asia, has been found in Wisconsin waters, where officials said it may not survive the winter cold.

“THIS WAS a real wake-up call,” said Mike Staggs, director of fisheries at the DNR.

The giant snakehead can grow to more than 3 feet (1 meter) in length, and fish managers say that with no natural predator, it could change the local fish population and introduce new diseases.

A year ago, wildlife officials in Maryland killed six adult and more than 1,000 juvenile northern snakehead, a close relative to the giant snakehead, found in a pond.

The DNR found the giant snakehead during a routine fish survey of the Rock River Sept. 4.

The DNR said an employee misidentified the fish as a native bowfin. It was photographed and released before the DNR later concluded it was a snakehead.

Two crews were sent back to the river last Thursday and three more crews went back Tuesday to look for evidence of snakeheads but found none, Staggs said.